Dialysis catheter

ABSTRACT

A dialysis catheter including a first portion having a first diameter, an elongated distal portion having a second smaller diameter, and a transition portion The first portion includes first and second independent blood withdrawal lumens extending in the first portion, the first withdrawal lumen terminating in the transition portion in a first terminal opening and the second withdrawal lumen terminating in a second terminal opening, the first and second terminal openings being radially spaced and axially adjacent. A longitudinally extending blood delivery lumen extends in the first portion and terminates in a delivery opening in the distal portion of the catheter, the first and second terminal openings positioned proximally of the delivery opening and each of the first and second terminal openings having a curved wall surrounding a portion of the terminal opening.

This application is a continuation of U.S. patent application Ser. No.13/947,088, filed Jul. 21, 2013, which is a continuation of U.S. patentapplication Ser. No. 12/497,574, filed Jul. 3, 2009, now U.S. Pat. No.8,500,674, which is a continuation of U.S. patent application Ser. No.12/079,716, filed Mar. 28, 2008, now U.S. Pat. No. 8,323,228, whichclaims priority from provisional application Ser. No. 60/923,101, filedApr. 12, 2007, and is a continuation-in-part of U.S. application Ser.No. 11/487,750, filed Jul. 17, 2006, which is a continuation ofapplication Ser. No. 10/279,468, filed Oct. 24, 2002, now U.S. Pat. No.7,077,829, which is a continuation-in-part of application Ser. No.10/025,506, filed Dec. 19, 2001, now U.S. Pat. No. 6,814,718, whichclaims priority from provisional patent application Ser. No. 60/260,592,filed Jan. 9, 2001. The entire contents of each of these applicationsare incorporated herein by reference.

BACKGROUND

Technical Field

This application relates to a catheter and more particularly to amulti-lumen catheter which facilitates hemodialysis.

Background of Related Art

Hemodialysis is a well known method of providing renal (kidney) functionby circulating blood. The kidneys are organs which function to extractwater and urea, mineral salts, toxins, and other waste products from theblood with filtering units called nephrons. From the nephrons thecollected waste is sent to the bladder for excretion. For patientshaving one or both defective kidneys, the hemodialysis procedure is lifesaving because it provides a machine to simulate the function of thekidneys.

In the hemodialysis procedure, blood is withdrawn from the patient'sbody through a catheter or tube and transported to a dialysis machine,also commonly referred to as a kidney machine. The catheter is typicallyinserted through the jugular vein and maneuvered into position throughthe superior vena cava into the right atrium to provide high blood flow.In the dialysis machine, toxins and other waste products diffuse througha semi-permeable membrane into a dialysis fluid closely matching thechemical composition of the blood. The filtered blood, i.e. with thewaste products removed, is then returned to the patient's body. In someinstances, the catheter may be left in place for several years. As canbe appreciated, proper access to the patient's blood and transport ofthe blood to and from the dialysis machine for this extended period oftime is critical to hemodialysis.

One example of a dialysis catheter currently being marketed is theMedComp Ash Split catheter. This catheter has two lumens, one forarterial flow and the other for venous flow, which are each D-shaped incross-sectional configuration. The catheter is bifurcated at its distalend to separate the lumens and the catheter is manually split to thedesired length for selected separation before insertion into the targetarea. Another well-known catheter is a Med Comp catheter which has thevenous flow lumen terminating proximally, i.e. axially recessed, fromthe arterial flow lumen. Each of these lumens is also D-shaped incross-sectional configuration.

These Medcomp dialysis catheters require numerous steps for insertion.The multiple insertion steps can be summarized as follows:

-   -   1. an introducer needle is inserted through a first incision        site (first opening) to properly locate (access) the vessel,        e.g. the right internal jugular vein;    -   2. a guide wire is inserted through the needle into the internal        jugular vein and down through the superior vena cava into the        inferior vena cava;    -   3. the introducer needle is withdrawn leaving the guidewire in        place;    -   4. a tear away (peel away) sheath and dilator are inserted over        the guidewire and through the first incision site to provide an        access port for the dialysis catheter into the jugular vein,        superior vena cava and right atrium;    -   5. a second incision is made in the chest wall to create a        second opening;    -   6. a trocar is attached to the distal end of the dialysis        catheter;    -   7. the trocar and dialysis catheter are pushed through the        second incision and advanced to bluntly dissect the subcutaneous        tissue to exit the first incision (opening) which was created by        the introducer needle, thereby creating a subcutaneous tissue        tunnel between the first and second openings;    -   8. the trocar is detached from the dialysis catheter leaving the        catheter in place extending from the second opening, through the        tissue tunnel and out the first opening;    -   9. the dilator and guidewire are removed, leaving the tear away        sheath in place in the first incision which has been expanded by        the dilator;    -   10. the dialysis catheter, which is protruding from the first        incision, is inserted through the tear away sheath and advanced        so its distal portion is positioned in the right atrium;    -   11. the sheath is separated, i.e. split, by pulling the tabs        apart, and then pulled upwardly away from the dialysis catheter        and removed from the body, leaving the catheter in place; and    -   12. the second incision is closed and the dialysis catheter,        which is connected through tubes to the dialysis machine, is        left in place an extended period of time to provide blood        circulation to and from the dialysis machine.

(Alternatively, in the foregoing method, the trocar can be forcedthrough a third incision exiting adjacent the first incision, and thenthe catheter inserted through second and third incisions and through theintroducer sheath positioned in the first incision.)

This multiple step process of inserting the Medcomp dialysis catheter istime consuming and complicates the surgical procedure. These multiplesteps add to the cost of the procedure, not only because of theadditional surgeon's time but because additional components, such as thetear-away sheath, are required which increases the overall cost of thecatheter system. Also, removal of the dilator increases the tendency ofthe sheath to kink causing difficulties in catheter insertion.

The use of the tear away sheath is also potentially problematic. Thetear-away sheath has lines of weakness to separate it as it is pulledapart by the pull tabs to enable removal of the sheath. However, thesheath can potentially cause damage to the vessel wall as it is beingpulled apart and can cause infection. Moreover, pulling the sheathlaterally can enlarge the incision, thereby increasing the difficulty ofclosing the incision at the end of the procedure. Also, since the sheathis pulled in the proximal direction for removal, it could pull thecatheter proximally as well, thereby pulling it away from the desiredsite, and requiring repositioning. The edges of the tear away can alsolacerate the surgeon's glove and finger. Over dilation by the sheath cancause blood leakage.

An additional potential risk with utilizing tear away sheaths is thatair embolism can occur. During the time the surgeon withdraws thedilator from the sheath and inserts the catheter, a passageway throughthe sheath to the vessel is open. If the patient inhales during thiscatheter exchange, an air bubble can enter the vascular system andobstruct the vessel, potentially causing stroke or even death.

It would therefore be advantageous if a dialysis catheter insertionmethod could be provided which reduces some of the foregoing proceduralsteps, thereby decreasing the complexity of the procedure and decreasingthe hospital and surgeon costs. It would also be advantageous if suchdialysis catheter insertion method could be provided which would be lesstraumatic and avoid the foregoing problems associated with the use of atear-away sheath, such as increased risk of air embolism, trauma to thevessel wall, incision enlargement and dislodgement of the catheter.

Another area of dialysis catheter insertion, which needs improvement, isguiding the catheter to the target site. Dialysis catheters are composedof flexible tubing to minimize damage to the vessel wall duringinsertion and use. This flexibility, however, oftentimes results inkinking of the catheter since the catheter must navigate curves to reachthe target vessel. This kinking can adversely affect blood flow. Also,the catheter needs to have some degree of stiffness to enable directingthe catheter around the curves of the vessels. The stiffness, howeverprovides its own risks since if the catheter is not properly directed,the catheter can inadvertently be forced against the vessel wall,thereby puncturing or damaging the vessel. Several different approacheshave been discussed in the prior art to increase stiffness of catheterssuch as providing a distal tip of stiffer material to guide the catheteras in U.S. Pat. No. 5,957,893, using materials of different durometersin various portions of the catheter (U.S. Pat. No. 5,348,536), placingan additional concentration of material in the tip as in U.S. Pat. No.4,583,968, or providing reinforcing strips, obturators or tubes withinthe catheter body to increase the rigidity (e.g. U.S. Pat. Nos.4,619,643, 4,950,259 5,221,255, 5,221,256, and 5,246,430). The needhowever exists to improve the balance between flexibility and stiffness.Thus it would be advantageous to provide a catheter with sufficientflexibility to accommodate anatomical curves of the patient while stillhaving sufficient stiffness to enable guiding the flexible cathetertubing atraumatically through the length of the vessels.

In navigating vessels to access the target site, such as the rightatrium, it is desirable to provide the smallest catheter profile, i.e.the smallest outer diameter catheter body. This profile facilitatesinsertion through smaller vessels as it reduces the likelihood of thecatheter engaging the wall of the vessel and reduces trauma to thevessel by minimizing frictional contact with the vessel wall. However,the desire for smaller diameter catheters must be balanced against theneed for providing sufficient sized lumens to enable proper blood flow.If the lumens are too small, sufficient blood flow may not be able to bemaintained and the blood can be damaged during transport. Also, asufficient relationship must be maintained between the size of thelumens and the overall diameter of the catheter to maintain thestructural integrity of the catheter.

Numerous attempts have been made in the prior art to optimize themulti-lumen configuration. In some approaches, such as disclosed in U.S.Pat. Nos. 4,568,329 and 5,053,023, inflow and outflow lumen are providedside by side in D-shaped form. In other approaches, such as thosedisclosed in U.S. Pat. Nos. 4,493,696, 5,167,623 and 5,380,276 theinflow and outflow tubes are placed in concentric relation. Otherexamples of different lumen configurations are disclosed in U.S. Pat.Nos. 5,221,256, 5,364,344, and 5,451,206. The lumen configuration mustaccommodate two competing factors: keeping the catheter as small aspossible to facilitate insertion while keeping the lumens as large aspossible for blood flow. This balance must be achieved while maintainingthe structural integrity of the catheter. It would therefore beadvantageous to provide a catheter which reaches an optimum compromisebetween these two competing factors.

Another important feature of dialysis catheters is the suction openingsto withdraw blood. Keeping the suction openings clear of thrombolyticmaterial and away from the vessel wall is clearly essential to dialysisfunction since an adequate supply of blood must be removed from thepatient to be dialyzed. However, a problem with prior dialysis cathetersis that during blood withdrawal, as suction is being applied through thecatheter openings and lumen, the suction can cause the catheter to beforced against the side wall of the vessel, known as “side portocclusion”, which can block the opening and adversely affect thefunction of the catheter by enabling only intermittent suction. In fact,the opening can become completely blocked, thereby preventing necessaryintake of blood, i.e. venous flow. Fibrin sheath growth around theoutside of the catheter can occur since dialysis catheters areoftentimes implanted for several months or even years. This fibringrowth, caused by the body's attempt to reject the catheter as a foreignbody, could result in blocking of the suction holes.

The need therefore exists for an improved dialysis catheter whichfacilitates the surgical dialysis procedure. Such catheter wouldadvantageously reduce the catheter insertion time, simplify the catheterinsertion process, eliminate the need for a peel-away introducer sheath,decrease the chances of infection, reduce unwanted kinking of thecatheter during insertion, strike an optimal balance between overallcatheter and lumen size, and improve the suction capability to avoidhampering of blood flow.

Co-pending, commonly assigned prior patent application Ser. No.11/487,750, filed Jul. 17, 2006, incorporated herein in by reference inits entirety, overcomes the disadvantages and deficiencies of the priorart. The dialysis catheter disclosed herein is a modification to thecatheter of the '750 patent and provides similar advantages over theprior art.

SUMMARY

The present invention provides a dialysis catheter comprising a firstportion having a first diameter, an elongated distal portion having asecond diameter smaller than the first diameter, and a transition regionbetween the first portion and distal portion. A first longitudinallyextending central lumen configured to deliver blood terminates in anopening in the distal portion. At least two independent longitudinallyextending lumens are positioned radially of the first lumen, configuredto withdraw blood from a patient, and terminate in a longitudinallydirected opening in the transition region.

Preferably the transition region tapers toward the distal portion andpreferably at least a portion of the wall thickness of the catheter inthe distal portion tapers toward a distalmost end with the central lumencross-sectional area remaining substantially constant throughout itslength in the distal portion.

The catheter may further comprise a stiffening member removablypositionable within the catheter to temporarily increase the stiffnessof the catheter to facilitate insertion.

The present invention also provides a medical catheter comprising afirst return lumen, a plurality of withdrawal lumens, a first clampingmember and a plurality of intake extension tubes. Each intake extensiontube communicates with an intake lumen of the catheter to provide fluidcommunication with the respective intake lumens. The intake extensiontubes are positioned in a stacked arrangement, and the clamping memberhas a plurality of posts to receive the stacked tubes to limit lateralmovement thereof.

The catheter preferably further comprises an independent venousextension tube communicating with the return lumen of the catheter.

In one embodiment, the catheter includes a first tag connected to thefirst clamping member and a second tag connected to the second clampingmember to provide information to the user. In one embodiment, the firsttag includes first and second side walls and a bridge extending betweenthe first and second side walls and the second tag includes first andsecond sidewalls and a bridge extending between the first and secondsidewalls.

The present invention also provides in combination a clamping member anda plurality of extension tubes of a medical catheter for delivering andwithdrawing blood from a patient's body. The plurality of intakeextension tubes each communicate with an intake lumen of the catheter toprovide fluid communication with the respective intake lumens. Theintake extension tubes are positioned in a stacked arrangement. Theclamping member has a plurality of posts to receive the stacked tubes tolimit lateral movement thereof.

In one embodiment, the combination further includes a luer and anadapter interposed between the plurality of intake extension tubes andthe luer. In a preferred embodiment, the adapter has three openingsarranged in a triangular arrangement to receive and reorient theextension tubes.

In a preferred embodiment a first tag is connected to the clampingmember to provide information to the user. The tag in one embodimentcomprises a first and second side wall and a bridge extending betweenthe first and second side walls.

The first clamping member in one embodiment has a pair of proximal postsand a pair of distal posts spaced axially from the proximal posts.

The combination may also include an independent venous extension tubecommunicating with a return lumen of the catheter, a second clampingmember for clamping the venous extension tube and a second tag connectedto the second clamping member. The second tag in one embodiment includesfirst and second sidewalls and a bridge extending between the first andsecond sidewalls.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiment(s) of the present disclosure are described hereinwith reference to the drawings wherein:

FIG. 1 is a plan view of a first embodiment of the multi-lumen catheterof the present invention being inserted through the right internaljugular vein and superior vena cava into the right atrium of a patient'sbody;

FIG. 2 is a plan view illustrating the multi-lumen catheter of FIG. 1being inserted through the left internal jugular vein and superior venacava into the right atrium;

FIG. 3 is an isometric view of the first embodiment of the multi-lumencatheter of the present invention and showing the direction of insertionof the stiffening rod;

FIG. 4A is a side view of a first embodiment of a stiffening rod of thepresent invention insertable through the catheter of FIG. 3 tofacilitate catheter insertion;

FIG. 4B is a side view of an alternate embodiment of the stiffening rodof the present invention having a series of mounting threads at itsdistal end;

FIG. 5 is perspective view of the distal portion of the multi-lumencatheter of FIG. 3 and showing a guidewire extending through the centrallumen;

FIG. 6A is a longitudinal cross-sectional view taken along lines 6A-6Aof FIG. 5;

FIG. 6B is a longitudinal cross-sectional view similar to FIG. 6A exceptshowing an alternate embodiment of the catheter having internal threadsfor securing the stiffening rod of FIG. 4B;

FIG. 7 is a transverse cross sectional view taken along lines 7-7 ofFIG. 6A;

FIG. 8 is a transverse cross sectional view taken along lines 8-8 ofFIG. 6A:

FIG. 9A is a transverse cross-sectional view similar to FIG. 8 exceptshowing a second alternate embodiment of the lumen configuration of thecatheter of the present invention;

FIG. 9B is a transverse cross-sectional view similar to FIG. 8 exceptshowing a third embodiment of the lumen configuration of the catheter ofthe present invention;

FIG. 9C is a transverse cross-sectional view similar to FIG. 8 exceptshowing a fourth embodiment of the lumen configuration of the catheterof the present invention;

FIG. 10 is a transverse cross-sectional view similar to FIG. 8 exceptshowing a fifth embodiment of the lumen configuration of the catheter ofthe present invention;

FIG. 11 is a longitudinal cross sectional view of the distal end portionof the catheter of FIG. 3 illustrating the stiffening rod of FIG. 4Abeing inserted through the central lumen of the catheter;

FIG. 12 is a longitudinal cross sectional view similar to FIG. 11 exceptshowing the stiffening rod fully positioned within the central lumen, inabutment with the stop in the distal tip;

FIGS. 13-15 illustrate an alternate embodiment of the distal tip of thecatheter of the present invention and the method steps for forming thetip wherein:

-   -   FIGS. 13A and 13B are perspective and cross-sectional views,        respectively, of the tip before formation shown receiving a        stiffening insert;    -   FIGS. 14A and 14B are perspective and cross-sectional views,        respectively, of the tip once the stiffening inserted has been        placed therein;    -   FIGS. 15A and 15B are perspective and cross-sectional views,        respectively, of the distal tip formed into a bullet nose        configuration and showing side holes formed therein;

FIG. 16A is a perspective view of a distal portion of another alternateembodiment of the multi-lumen catheter of the present invention having aseries of spacer wires and showing a guidewire extending therethrough;

FIG. 16B is a longitudinal cross-sectional view of the distal portioncatheter of FIG. 16A showing the spacer wires in the extended position;

FIG. 16C is a longitudinal cross-sectional view similar to FIG. 16Aexcept showing the profile of the spacing wires and catheter bodyreduced as the stiffening rod of FIG. 4A is inserted into the centrallumen over the guidewire to stretch the catheter during insertion;

FIG. 17A is a perspective view of a distal portion of yet anotheralternate embodiment of the catheter having a series of integral spacerribs;

FIG. 17B is a longitudinal cross-sectional view of the distal portion ofcatheter of FIG. 17 showing the spacer ribs in the extended position;

FIG. 17C is a longitudinal cross-sectional view similar to FIG. 17Aexcept showing the profile of the spacer ribs and catheter body reducedas the stiffening rod of FIG. 4A is inserted into the central lumen tostretch the catheter during insertion;

FIG. 18 is a perspective view of a distal portion of another alternateembodiment of the multi-lumen catheter of the present invention having atapered tip;

FIG. 19 is a longitudinal cross-sectional view of the distal portion ofthe catheter of FIG. 18 showing the stiffening rod positioned throughthe central lumen of the catheter over the guidewire;

FIG. 20 is a perspective view of a distal portion of yet anotheralternate embodiment of multi-lumen catheter of the present invention;

FIG. 21A is a perspective view of a first embodiment of a trocar of thepresent invention having a barbed proximal end for attachment to thecatheter for creating a subcutaneous tissue tunnel and for pulling thecatheter through the tissue tunnel;

FIG. 21B is a perspective exploded view of an alternate embodiment ofthe trocar of FIG. 21A having a removable handle;

FIG. 21C is a close up view of the connecting structure of the trocar ofFIG. 21B;

FIG. 21D is a close up view of an alternate embodiment of the trocarhaving a threaded connecting structure;

FIG. 21E is a perspective view of the trocar of FIG. 21B being insertedthrough a subcutaneous tissue tunnel;

FIG. 21F is a transverse cross-sectional view taken along lines 4-4 ofFIG. 21E showing the latch for releasably connecting the trocar of FIG.21B to the handle;

FIG. 21G is a cross-sectional view showing the threaded connection ofthe trocar of FIG. 21D to the handle;

FIG. 21H is a perspective view of another alternate embodiment of thetrocar having a series of threads distal of the barbed fitting;

FIG. 21J is a perspective view of an alternate embodiment of a trocarwith a proximal end configured for insertion into a distal end of thecatheter;

FIG. 21K is an enlarged side view of the proximal end of the trocar ofFIG. 21J;

FIG. 21L is a perspective view showing insertion of the trocar of FIG.21J into the distal end of the catheter;

FIG. 21M is a perspective view showing the trocar of FIG. 21J attachedto the catheter.

FIG. 22 illustrates an alternate embodiment of the trocar of the presentinvention having a lumen for receiving a guidewire;

FIG. 23 illustrates the trocar of FIG. 22 being withdrawn after asubcutaneous tissue tunnel has been created;

FIG. 24A is a bottom view of another alternate embodiment of the trocarof the present invention having a lumen for receiving a guidewire;

FIG. 24B is a longitudinal cross-sectional view of the distal endportion of the trocar of FIG. 24A;

FIGS. 25-28 illustrate the surgical method steps for inserting themulti-lumen catheter of FIG. 3 through the right internal jugular veinand superior vena cava into the right atrium wherein:

-   -   FIG. 25 shows the introducer needle being inserted through the        right jugular vein and the guidewire being inserted through the        right jugular vein, through the superior vena cava and into the        right atrium;    -   FIG. 26 illustrates the needle introducer removed leaving the        guidewire in place in the right internal jugular vein, superior        vena cava and right atrium;    -   FIG. 27 illustrates the trocar of FIG. 22 being inserted through        a first incision site and exiting a second incision site to        create a subcutaneous tissue tunnel adjacent the incision site        for the introducer needle;    -   FIG. 28A illustrates the guidewire being threaded through the        lumen of the trocar of FIG. 22;    -   FIG. 28B illustrates the trocar being removed, leaving the        guidewire in place extending through the tissue tunnel; and    -   FIG. 28C illustrates the multi-lumen catheter of FIG. 3 inserted        over the guidewire through the tissue tunnel, and curved down        into the right internal jugular vein, superior vena cava and        right atrium;

FIGS. 29A-29G illustrate the steps for an alternate method of insertingthe multi-lumen catheter of FIG. 3 through the right internal jugularvein and superior vena cava into the right atrium wherein the trocarcreates a tissue tunnel with an exit opening at the incision cite wherethe needle and guidewire are introduced, wherein:

-   -   FIG. 29A illustrates the trocar of FIG. 22 inserted over the        guidewire through a first incision site, creating a subcutaneous        tissue tunnel, and exiting the incision site created for        insertion of the introducer needle and guidewire;    -   FIG. 29B illustrates the trocar being removed, leaving the        guidewire in place extending through the tissue tunnel and        forming a loop adjacent the needle incision site; and    -   FIG. 29C illustrates the multi-lumen catheter of FIG. 3 being        inserted over the guidewire for passage through the tissue        tunnel;    -   FIG. 29D illustrates the catheter inserted through the        subcutaneous tissue tunnel and forming a loop corresponding to        the loop formed in the guidewire,    -   FIG. 29E illustrates the catheter extending through the        subcutaneous tissue tunnel and being inserted further along the        guidewire down into the right internal jugular vein;    -   FIG. 29F is a view similar to FIG. 29E except showing the        guidewire being removed; and    -   FIG. 29G illustrates the catheter in place extending through the        subcutaneous tissue tunnel and advanced into the right internal        jugular vein, superior vena cava and right atrium;

FIG. 30 illustrates an alternate method of retracting the guidewirethrough the subcutaneous tissue tunnel formed by the trocar;

FIGS. 31-37 illustrate a method for manufacturing a first embodiment ofthe hub of the multi-lumen catheter of FIG. 3 wherein:

-   -   FIG. 31 illustrates a slit formed in the outer wall of the        catheter;    -   FIG. 32 is a view similar to FIG. 31 except showing in phantom        the central arterial lumen of the catheter;    -   FIG. 33 is a transverse cross-sectional view taken along lines        33-33 of FIG. 32;    -   FIG. 34 illustrates a pin inserted through the slit in the outer        wall of the catheter;    -   FIG. 35 illustrates the tubing inserted over the pin;    -   FIG. 36 illustrates the injection of soft material over the pin        and catheter tube to form the catheter hub which retains the        lumen connector tubes in position;    -   FIG. 37 illustrates the hub resulting from the injection molding        process enabling one connector to communicate with the inflow        (arterial) lumen and the other connector to communicate with the        multiple outflow (venous) lumens;

FIGS. 38-40 illustrate an alternate embodiment of the hub of themulti-lumen catheter of FIG. 3 wherein;

-   -   FIG. 38 illustrates a perspective view of the proximal end of        the catheter body split into five segments to accommodate the        separate connector tubes;    -   FIG. 39 is a perspective view illustrating the connector tubes        inserted into the respective lumens of the catheter body; and    -   FIG. 40 is a transverse cross-sectional view illustrating the        cuts made in the catheter wall to form the separate segments.

FIG. 41 is a perspective view of another alternate embodiment of the hubof the catheter of the present invention having the lumen configurationof FIG. 9C;

FIG. 42 is an exploded view of the hub and tube structure of FIG. 41;

FIG. 43 is an enlarged perspective view showing the transition of thevenous holes from a substantially oval to a substantially roundconfiguration at the flared proximal portion of the catheter; and

FIG. 44 is an enlarged perspective view showing the multi-lumenextension tube tapering proximally and transitioning from substantiallycircular venous holes to substantially triangular holes;

FIGS. 45-54 illustrate an alternate preferred embodiment of the dialysiscatheter of the present invention, wherein

-   -   FIG. 45 is a perspective view of the catheter;    -   FIG. 46 is a perspective view similar to FIG. 45 except showing        the stiffener rod positioned therein;    -   FIG. 47 is an enlarged perspective view of the catheter tip        showing the return and intake lumen openings;    -   FIG. 48 is a side view of the catheter tip;    -   FIGS. 48A, 48B and 48C are transverse cross-sectional views        taken along lines A-A, B-B and C-C, respectively, of FIG. 48;    -   FIG. 49A is a longitudinal cross-sectional view of a distal        portion of the catheter showing the stiffener rod extending        through the catheter;    -   FIG. 49B is a side view of the stiffener rod of FIG. 49A;    -   FIG. 50 is a perspective view showing the arterial extension        tubes extending from the proximal flared portion of the        catheter, the venous extension tube is removed for clarity;    -   FIG. 51 is a side view of the proximal end of the catheter, with        one of the hub halves removed, showing the extension tubing        connections to the catheter lumens;    -   FIG. 52 is a perspective view of a proximal portion of the        arterial extension tubing illustrating the funneled surfaces for        wire insertion;    -   FIG. 53 is a transverse cross-sectional view taken along lines        D-D of FIG. 46 showing the lead in for the cleaning wire        insertion; and    -   FIG. 54 is a transverse cross-sectional view taken along lines        E-E of FIG. 50 showing the arterial extension tubes within the        sheath.

FIG. 55 is a perspective view of the proximal end portion of analternate embodiment of the catheter of the present invention showingthe extension tubing and clamps;

FIG. 56 is an exploded view of the catheter of FIG. 55;

FIG. 57A is a perspective view of a distal end portion of the catheter;and

FIG. 57B is a transverse cross-sectional view illustrating the lumenconfiguration of one embodiment of the catheter;

FIG. 57C is a transverse cross-sectional view illustrating the lumenconfiguration of an alternate embodiment of the catheter;

FIGS. 58A and 58B are side and perspective views, respectively, of thearterial clamp shown in the open position;

FIGS. 59A and 59B are perspective and top views, respectively, of thearterial tag;

FIG. 60 is a perspective view of the adapter;

FIG. 61A is a perspective view of the venous clamp in the neutralposition;

FIGS. 62A and 62B are perspective and top views, respectively, of thevenous tag;

FIG. 63 is an enlarged view of the arterial clamp shown in the openposition and further showing a portion of the venous clamp, a portion ofthe arterial and venous tags removed for clarity; and

FIG. 64 is an enlarged view of the venous clamp shown in the neutralposition and further showing a portion of the arterial clamp.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now in detail to the drawings where like reference numeralsidentify similar or like components throughout the several views, thefirst embodiment of the catheter of the present invention is designatedgenerally by reference numeral 10. The catheter 10 is typically insertedinto an area of high velocity blood flow to ensure sufficient blood canbe transported from the body for dialysis. FIG. 1 illustrates thecatheter 10 inserted through the right internal jugular vein “a”, intothe superior vena cava “b”, and into the right atrium “c”; FIG. 2illustrates the catheter 10 inserted into the left internal jugular vein“d”, into the superior vena cava “b” and into the right atrium “c”.Insertion into the right atrium, from either the right or left sideprovides the necessary high blood flow to the dialysis machine. Notethat the catheter body (catheter tube) 11 is sufficiently flexible toenable it to bend to accommodate the anatomical curves as shown.

Catheter 10 has a catheter body or catheter tube 11 having a distal endportion 31, a proximal end portion 33, and an intermediate portion 35.Distal portion 31 terminates in nose 32 which is illustrativelysubstantially conical in shape. Proximal end portion 33 includes hub 12,where the lumens formed within catheter tube 11 are connected, i.e.transition, to the respective inflow and outflow tubes, 16, 18,respectively, to enable return and withdrawal of blood for dialysis.Conventional tube clamps 17 and 19 cut off blood flow through inflow andoutflow tubes 16, 18 as desired. As used herein, the terms “inflow” and“outflow” refer to the direction of blood flow with respect to thecatheter such that “return”, “delivery” or “venous flow” refers to flowfrom the dialysis machine and delivered to the body while “intake”,“withdrawal” or “arterial flow” refers to flow withdrawn from the bodyand transported to the dialysis machine.

As shown, intermediate portion of catheter 10 extends throughsubcutaneous tissue tunnel “t”, and curves downwardly toward the targetsite, e.g. the right atrium. This tunnel “t” secures the catheter inplace for dialysis for a period of weeks, or even months, with fibrouscuff 36 (FIG. 3) enabling tissue ingrowth. The formation of the tunnel“t” and the insertion of the catheter 10 therethrough will be discussedbelow in conjunction with the discussion of the catheter insertionmethod.

It should be appreciated that although the catheter is shown emergingfrom the tissue tunnel “t” at a second incision site, preferably, thetissue tunnel would not have an exit opening at a second site butinstead would exit through the same incision through which initialaccess is made by the needle and dilator into the internal jugular vein“a”. This is described in more detail below.

A series of lumens are formed in catheter tube 11 for transporting bloodto and from a dialysis machine. As is well known in the art, a dialysismachine essentially functions as a kidney for patients suffering fromkidney failure. Blood is removed from the patient and transported to thedialysis machine where toxins are removed by diffusion through asemi-permeable membrane into a dialysis fluid. The filtered blood isthen returned through the catheter body to the patient.

More specifically, and with reference to FIGS. 5, 6A, 7 and 8, detailsof the catheter lumens will now be described. Central longitudinal lumen40 is formed within catheter tube 11, extends the entire length and isdesigned to transport filtered blood to the patient. Lumen 40 is alsoconfigured to receive a guidewire 20 to direct the catheter to thedesired position. Lumen 40 extends to nose 42, and terminates in region37 where it aligns with central longitudinal lumen 41 of nose 42.Central lumen 41 of nose 42 communicates with narrowed lumen 45,terminating in distal opening 47 to communicate with the patient's bodyso blood can be delivered through distal opening 47. Lumens 41 and 45also receive guidewire 20. Thus, lumen 40, lumen 41 and narrowed lumen45 together form a central lumen enabling blood to be delivered from thedialysis machine to the patient. The transition from lumen 41 intonarrowed lumen 45, forms a stop or shoulder 43, the function of whichwill be described below.

Nose 42 also includes side venous (delivery) openings 46 formed throughthe outer wall 44 wall in fluid communication with lumen 41, alsofunctioning to return blood to the patient's body. Side openings orports 46 are preferably angled outwardly as shown to facilitate deliveryof blood in the direction of blood flow and lessen mechanical hemolysis.These additional openings help maintain the desired flow volume bydistributing the blood through multiple holes. Although only fouropenings are shown, it is contemplated that additional or fewer openingscan be provided and the openings can be axially displaced with respectto each other. Additional set(s) of openings can also be provided spacedproximally or distally from side openings 46.

In this embodiment, nose 42 forms the distal tip portion and is composedof a different material than the other portions of the catheter body 11and is welded or attached by other means to the catheter body 11. Thetip (nose) in this embodiment is composed of a stiffer material tofacilitate tunneling and blunt dissection through tissue. The nose couldalternatively be composed of a softer material, thereby being lesstraumatic upon contact with the vessel wall. However, in a preferredembodiment, the nose is composed of the same material as the catheterbody, having a small stiffener member embedded therein. Thisconfiguration is described in detail below in conjunction with FIGS.13-15.

Catheter 10 also has a series of arterial (withdrawal) lumens 34 a-34 e,extending longitudinally along the length of the catheter body 11, eachterminating at surface 48 of nose 42. In the preferred embodiment, shownin the cross-sectional view of FIG. 8, the lumens 34 are oval-like inconfiguration, with opposite curved walls 37 a, 37 b and oppositesubstantially flat walls 39 a, 39 b. These spaced apart lumens havesolid material between them therefore increasing the structuralintegrity of the catheter body 11. The lumens 34 a-e are independentfrom one another through the distal, intermediate and proximal portions33, 35, 31 of the catheter body 11, until the hub 12 where the lumens 34a-34 e connect to a common connector tube. This is described in moredetail below. Lumens 34 a-34 e, as shown, are symmetrically positionedand radially displaced from the central return lumen 40.

With continued reference to FIGS. 5 and 6A, a series of side openings orports 50 are provided in the outer wall 14 of catheter body 10. Theseopenings 50 a, 50 b, 50 c, 50 d, and 50 e are each in fluidcommunication with a respective intake lumen 34 a-34 e and are designedand configured to withdraw blood from the patient's body for delivery tothe dialysis machine. A second set of openings 52 a-52 e, spacedproximally from openings 50 a-50 e, is also in communication with arespective lumen 34 a-34 e. Only three of the side openings 50, 52 areshown in FIG. 5, it being understood that the other three openings arepositioned on the other side of the catheter, preferably symmetricallyplaced to accommodate the circumferential arrangement of the intakelumens 34 a-34 e.

Although lumens 34 a-34 e are isolated along a substantial length of thecatheter, they preferably have a common flow source at the proximalportion 33 of the catheter 10. This is described in more detail below.

In the embodiment of FIG. 8, the venous (return) lumen size preferablyranges from about 0.006 inches to about 0.008 inches² in cross-sectionalarea, and is more preferably 0.007 inches². The cross-sectional area ofeach of the arterial (intake) lumens 34 preferably ranges from about0.002 inches to about 0.004 inches², and more preferably about 0.003inches², bringing the total cross-sectional area of the intake lumens toabout 0.01 inches to about 0.02 inches², and more preferably about 0.015inches². This means that the ratio of total cross sectional area of thereturn lumen to the intake lumens is about 1 to about 2.1. Otherdimensions are also contemplated.

It should be appreciated that although five separate lumens 34 areshown, a fewer or greater number can be provided. Also, although twosets of side openings are shown (set 50 and set 52), a fewer or greaternumber of sets can be provided, and a fewer or greater number ofopenings in each set could be provided.

Alternative lumen configurations spaced circumferentially areillustrated in FIGS. 9A, 9B, 9C and 10. In FIG. 9B, three arc-shapedlumens 60 a, 60 b, 60 c are positioned around the arterial central lumen40′. These larger sized lumens provide for additional arterial (intake)flow but result in the reduction of the strength of the catheter walldue to the less wall material as compared to the lumen configuration ofFIG. 8. In FIG. 9A, five lumens 66 a, 66 b and 66 c are provided. Theselumens have more of a rectangular (or trapezoidal) shape with one pairof opposing walls having a straighter configuration than the lumenconfiguration of FIG. 8. As shown, the other pair of opposing walls hasa slight curvature. In FIG. 9C, four oval-like intake lumens 76 a, 76 b,76 c and 76 d are positioned around a substantially square central lumen78. This lumen configuration provides for a substantially sized centrallumen and sufficient room between the central lumen 78 and each of theintake lumens 76 a-76 d for the catheter walls to flex. In FIG. 10, fivelumens 70 a-70 e of circular cross-section are provided around thecentral lumen 40″, adding to the stability of the catheter by increasingthe wall material, but reducing the overall venous lumen size ascompared to the embodiment of FIG. 8. Preferably, the intake (arterial)lumens in each of these embodiments are independent from one anotheralong the substantial length of the catheter.

Fewer or greater number of lumens could be provided and lumens of otherconfigurations are also contemplated. This positioning of the intakelumens in a circle-like array around the catheter, i.e. radiallydisplaced from the center of the catheter, more evenly distributes thevacuum, as compared to a side by side venous/arterial lumenconfiguration, and ensures constant return flow since if one of thelumens becomes stuck against the vessel wall or otherwise clogged, theremaining lumens will maintain adequate flow. The openings in thesidewalls communicating with the lumens can also be elongated instead ofcircular, creating a series of longitudinally extending openings forentry of suctioned blood. This version of elongated openings is shownfor example in FIGS. 18 and 20 described in detail below.

To facilitate insertion, the catheter is configured to receive astiffening member in the form of a stiffening rod which stretches thecatheter to reduce its profile to aid in over the wire insertion andbetter navigate through small vessels. That is, the stiffening rod isinserted into central lumen 40 of catheter 10 and torqued to stiffen theflexible catheter for ease in over the wire insertion and navigationthrough the small vessels, and to reduce the outer diameter of thecatheter body by stretching it during insertion. After placement of thecatheter 10, the stiffening rod is removed, allowing the catheter toreturn to its higher profile position with the lumens of the necessarysize for blood transport to and from the body. Two embodiments of thestiffening rods are illustrated in FIGS. 4A and 4B and are shown priorto insertion into the catheter 10 in FIG. 3. A third embodiment of thestiffening rod is illustrated in FIG. 49.

Turning to the first embodiment of the stiffening rod illustrated inFIG. 4A, the stiffening rod is designated generally by reference numeral80. Stiffening rod 80 has a distal tip 82, a proximal end portion 85 andan internal lumen 87 extending therethrough (see FIG. 11). Stiffeningrod 80 is inserted through the proximal end of inflow tube 16, in thedirection of the arrow of FIG. 11, over the guidewire 20 (which extendsthrough lumen 87 and through central lumen 40) until distal tip 82 abutsshoulder or stop 43 as shown in FIG. 12. The proximal end portion 85 ofstiffening rod 80 has a threaded portion 81 which is screwed onto screwthread 15 of inflow tube 16. This temporarily secures the stiffening rod80 within the catheter 10 during insertion. This threaded mountingrequires the stiffening rod 80 to be manually twisted, thereby torquingrod 80 as it presses forwardly and applies a force against shoulder(abutment surface) 43 to stretch the catheter body 11 to reduce itsouter diameter. It is contemplated in one embodiment, for example, thatthe catheter body 11 can be reduced in diameter from about 0.215millimeters to about 0.207 millimeters by the stiffening rod 80. (Othersize reductions are also contemplated). This reduction in catheter bodydiameter or profile is represented by the arrows D1 and D2 in FIGS. 11and 12, respectively, which show the change in dimension effectuated bythe stiffener rod 80.

After the catheter 10 is positioned at the desired site, the stiffeningrod 80 is unthreaded from the proximal thread 15 of venous (return) tube16 and removed from the central lumen 40 of the catheter 10 and from thevenous (return) tube 16, thereby allowing the catheter to return to itsnormal profile of FIG. 11.

It should be appreciated that stiffening rod 80 can alternatively betemporarily attached at its proximal end to the tube 16 by other meanssuch as a bayonet lock, snap fit, etc. The rod could first be manuallytwisted and then mounted by these various means for retention in itstorqued position.

An alternate embodiment of the stiffening rod is illustrated in FIG. 4Band designated generally by reference numeral 90. Stiffening rod 90 hasa threaded distal end 92 which is threaded onto internal threads 251 ofcatheter 200 shown in FIG. 6B. A series of proximal threads 91 arescrewed onto the threads 15 of the inflow tube 16 in the same manner asdescribed above for stiffener rod 80. The stiffening rod 90 functions inthe same manner as stiffening rod 80, i.e. to stretch the catheterduring insertion to reduce its profile and to stiffen it to facilitateinsertion, the only difference being the mechanical threaded attachmentof the distal end of the stiffening rod 90 to the catheter 200 insteadof the abutting relation of stiffening rod 80 with shoulder 43 ofcatheter 10. Preferably, the distal threads 92 are first threaded ontointernal thread 251, followed by attachment of the proximal threads 91as the stiffening rod 90 is torqued. Stiffening rod 90, like stiffeningrod 80, is preferably circular in cross-section, although otherconfigurations are also contemplated.

Catheter 200 of FIG. 6B is identical to catheter 200 in all respectsexcept for the threads 251 instead of shoulder 43 and lumen 241 which isuniform in diameter. Similar to catheter 10, catheter 200 has distalreturn opening 247 and side openings 246 in outer wall 244 communicatingwith lumen 241 in distal tip portion 242, which communicates withcentral lumen 40. Arterial intake lumens 234 a-234 e terminate at wall248 and have respective side openings 252 a-252 e and 250 a-250 e formedin the outer wall 214. Only one of the side openings 250 a, 252 a areshown in the longitudinal cross-sectional view of FIG. 6B.

As noted above, distal tip (nose) can be composed of a different stiffermaterial than the catheter body 11 or can be composed of a materialhaving a higher durometer than the catheter body. This stiffer materialwill facilitate both tunneling through and dilating tissue. In analternate preferred embodiment, however, the distal tip is composed ofthe same material as the catheter body but has a stiffening insert.

More specifically, the alternative nose (tip) configuration isillustrated in FIG. 15, with the method of manufacturing the tip shownin FIGS. 13 and 14. This nose or distal tip 104, is composed of the samematerial as the catheter body 108 and has a stiffening insert 110inserted through central lumen 106 of nose 104. Central lumen 106extends through the catheter body. The stiffening insert 110 ispreferably composed of the same material as the catheter body 11 andnose 104, except it is made of a harder durometer material such as 72shoreD vs. 85 shoreA for the catheter body 11. The material utilized canbe, by way of example, urethane. For convenience, only the distal tip isshown, the remaining portions of the catheter 100 being identical tocatheter 10.

The stiffening insert 110, preferably cylindrical as shown, has a hole112 for receipt of the guidewire and for communication with centrallumen 106. Insert 110 engages the inner wall surface 114 of centrallumen 106. Lumen 106, proximal of side openings 119, will include eithera stepped portion to provide an abutment surface (shoulder) forstiffening rod 80 or internal threads to mount stiffening rod 90 asdescribed above.

The method of manufacturing this bullet shaped nose 104 will now bedescribed in conjunction with FIGS. 13-15. Once cylindrical tube isformed, preferably by injection molding techniques, with central returnlumen 106 and intake lumens 109 a-109 e, stiffening insert 110 is placedwithin central lumen 106 at the distalmost end and substantially flushwith the distalmost edge 102 of the cylindrical tube.

Once the stiffening insert or slug 110 is placed within central lumen106, the tube is formed into the bullet nose shape of FIGS. 15A and 15B,by a conventional radiofrequency or other heating process which allowsthe tip material to flow and form around the harder insert 110. Afterheating of the die and formation into this configuration, the materialis cooled and thereby hardens to the configuration of FIG. 15 as thematerial fuses to the insert 110. A conventional core pin (not shown)can be used, inserted through the hole 112 and central lumen 106 duringthe forming process. When the material hardens, the pin is withdrawn tomaintain these openings. After the forming process, side holes 114 areeither cut or drilled through the wall 108 of catheter 100 tocommunicate with lumen 106 in the same manner as side holes 46communicate with central lumen 40 of FIGS. 1-6.

FIGS. 16A-17C illustrate two alternate embodiments of the catheter ofthe present invention having spacers to minimize contact of the catheterbody with the vessel wall. Provision of these spacers is optional. Inthe embodiment of FIGS. 16A-16C, catheter 150, similar to catheter 10,has a distal portion having a nose 154, a central return lumen 156 whichalso receives a guidewire 20, and a series (e.g. 5) of intake lumens160-160. Venous return lumen 156 communicates with lumen 151 andnarrowed lumen 153 of the nose 154, terminating in open distal end 158.A plurality of side openings 159 communicate with lumen 151 and functionin the same manner as side openings 46 of catheter 10. Arterial intakelumens 160 each terminate at side openings 161, similar to side openings52 of intake lumens 34 of catheter 10. Although only one series of sideopenings 161 are shown, clearly additional arrays of side openings,positioned distally or proximally of side openings 161 could beprovided. The arterial lumen configuration can also vary in a similarmanner as described above with respect to catheter 10. Thus, except forthe spacers, catheter 150 is identical to catheter 10.

A plurality of spacer wires 164 are embedded in the wall 169 of thecatheter 150 and are secured at region 158 by adhesive or other suitablemeans. In the normal configuration, spacer wires 164 bow slightlyoutwardly with respect to the outer wall 169 of the catheter 150 toreduce the likelihood of contact with the vessel wall. When thestiffening rod 80 is inserted over guidewire 20 and through centrallumen 156, as shown in FIG. 16C, and edge 170 is forced against theabutment surface or stop 159, the catheter body is stretched and thespacer wires 164 stretch to a straightened position, substantially flushwith the outer surface of wall 169. This reduces the profile of thecatheter and ensures the spacer wires do not interfere with catheterinsertion. When the stiffener rod 80 is withdrawn, the catheter returnsto its normal position, and the spacer wires 164 bow outwardly as inFIGS. 16A and 16B. It should be appreciated that stiffening rod 90 canalso be used with catheter 150 and would function to reduce the profilein the same manner as rod 80. Catheter 150 would then be provided withinternal threads for mounting stiffening rod 90 as described above.

An alternative to spacer wires is illustrated in FIGS. 17A-17C. Catheter180 is identical to catheter 150, except it is provided with integralribs 194 proximal of nose 184. That is, similar to catheter 150,catheter 180 has a central return lumen 186 configured to receiveguidewire 20 and stiffening rod 80 or 90. Lumen 186 communicates withlumen 181 and narrowed lumen 183 of the nose 184 which terminates inopen distal end 188. Side openings 189 of nose 184 communicate withlumen 181. A series of independent intake lumens 190 are provided,terminating in side openings 192, similar to side openings 161 ofcatheter 150. Although only one series of side openings 192 are shown,clearly additional arrays, positioned proximally or distally of sideopenings 192 could be provided.

Spacer ribs 194 are formed by cutout portions in the wall 193 of thecatheter 150. FIG. 17B illustrates the spacer ribs 194 in their normalposition, outwardly bowed from the outer surface of the wall 193 of thecatheter body. FIG. 17C illustrates the straightened or retractedposition of the spacer ribs 194, where the ribs 194 are substantiallyflush with the outer surface of wall 193, after stiffener rod 80 of FIG.4A (or rod 90 of FIG. 4B) is inserted through central lumen 186 tostretch the catheter 150 for insertion in the manner described above.

FIGS. 18 and 19 illustrate another alternative embodiment of thecatheter of the present invention. Catheter 500 has a distal tip 502with a tapered region 510 transitioning to a reduced diameter region504. The central lumen terminates in distal opening 506 for fluiddelivery. Unlike the previously described embodiments, the distalopening 506 is the sole fluid delivery passageway into the body.However, it is also contemplated that additional side holes could beprovided in the tip to provide additional venous ports for blooddelivery to the patient.

A series of intake (arterial) openings 508 (only two are shown in theview of FIG. 18) are provided in the transition or tapered region 510 ofthe tip 502. These openings are elongated to provide additional area forsuctioning. Each of the openings 508 communicates with a respectivearterial lumen 510 formed in the catheter. The venous lumenconfiguration (and arterial lumen configuration) can be in the form ofthose illustrated in FIGS. 7-10, or other variations, as describedabove.

Stiffening rod 520 is shown positioned in the central lumen of thecatheter 500. Rod 520 is similar to the rods 80 and 90 described aboveexcept it extends distally of the distal tip 502 of catheter 500, has atapered distal end 524 to facilitate tunneling and dilating tissue, andhas a stepped portion to abut the internal structure of the catheter500. More specifically, guidewire 20 is shown extending through thecentral lumen of stiffening rod 520. The stiffening rod 520 is insertedthrough the central lumen of catheter 500 and the stiffening rod 520 andcatheter 500 are inserted over the guidewire 20, with the tapered tip524 facilitating passage of the catheter as it dilates tissue.

Catheter 500 has a cylindrical insert 514 positioned in the distal tip,similar to insert 110 of FIG. 13A. The insert 514 is composed of astiffer material to stiffen the tip of the catheter 500 to facilitateinsertion. Insert 510 has an opening to receive stiffening rod 520 asshown. Shoulder 526 formed by stepped portion 524 abuts the insert 514,thereby functioning as a stop in a similar manner that shoulder 43 actsas a stop for stiffening rod 80 shown in FIG. 11, the difference beingthe shoulder is formed in the internal wall of the catheter rather thanon the stiffening rod. Stiffening rod 520 thus acts in the manner as theaforedescribed rods 80, 90, i.e. pressing against the catheter tipportion to stretch the catheter for insertion, in addition to providinga tissue tunneling and dilation function.

FIG. 20 illustrates an alternative tip design of the catheter of thepresent invention. Catheter tip 602 has a bullet nose configuration,somewhat similar to the nose of FIG. 15, except having more of aprogressive taper. Catheter tip 602 also has a series of elongatedintake holes 608 (only two are shown in the view of FIG. 20). In allother respects, e.g. stiffening insert, stiffening rod, distal blooddelivery opening 606, etc, catheter 600 is identical to catheter 500 ofFIG. 18.

FIGS. 45-54 illustrate another alternate embodiment of the catheter ofthe present invention, designated generally by reference numeral 800.Catheter 800 has a catheter body or catheter tube 810 having a distalportion 812 and a transition portion 814 between the distal portion 812and an intermediate portion 816 of the catheter. The proximal portion818 of catheter body 810 has a flared region as will be described below.

With reference to FIGS. 45 and 47, the distal portion 812 of catheter800 is elongated and has a diameter less than the diameter of theintermediate portion 816. By way of example, in one embodiment, thediameter of the distal portion 812 can be about 0.118 inches and thediameter of the intermediate portion 816 can be about 0.218 inches.Clearly other dimensions are contemplated.

The transition portion 814 provides a smooth transition between theintermediate portion 816 and the distal portion 812 as it tapers in adistal direction. Formed in the transition portion 814 are four widenedsomewhat trapezoidal open areas, separated by ribs 849, each extendinglongitudinally to communicate with the intake openings. Thus, the intakeopenings terminate in longitudinally aligned openings at the transitionportion 814.

The distal portion 812 has a non-uniform wall thickness with two taperedregions, best shown in FIG. 49. The wall thickness remains substantiallyconstant until slightly proximal of the transition region 814 where itincreases in thickness over a portion of the length, beginning atportion 819. The wall thickness of distal portion 812 then decreasestowards the distal end at region 817 forming a first taper. A secondtaper 813 is formed at the distalmost end. In one embodiment the firsttaper at region 817 is about 2 degrees and the distalmost end taper atregion 813 is about 5 degrees, although clearly other tapers arecontemplated. These tapered regions provide for easier insertion of thecatheter 800. Since the tapers are created by a change in wallthickness, the cross-sectional area of the central return lumen remainsconstant and the venous pressure is unaffected.

Embedded in the distal portion 812 is a stiffening insert 820 similar tothe cylindrical stiffening insert 110 described in conjunction withFIGS. 13A-15B, except it is located proximal of the distalmost tip. Thestiffening insert 820 is placed during formation of the catheter tube bymelting the catheter material around the insert during formation in asimilar fashion as insert 110.

FIG. 48 illustrates the lumen configuration of the catheter 800 which issimilar to the lumen configurations of FIG. 9C. A central return(venous) lumen 830 is encircled by a series of intake lumens 840 a-840 din a spoke-like fashion. The central return lumen 830 is substantiallysquare in cross-section with rounded corners as shown in FIG. 48A. Thefour intake lumens 840 a-840 d are oval-like in cross section with asubstantially planar edge 842 a-842 d and opposing inwardly angled sidewalls. The central lumen 830 terminates in opening 832 at the distalmostend of the catheter tube 810. The intake lumens are independent and eachterminates in an open area 844 a-844 d in the transition region 814 asdescribed above.

In a preferred embodiment, the central return lumen 830 is ofsubstantially constant cross-sectional area throughout its length. Atthe distal portion 812 the lumen 830 transitions to a more circularshape (FIG. 48B), but the cross-sectional area preferably remains thesame. In a preferred embodiment, the cross-sectional area of the centrallumen is about 0.007 inches², although other dimensions arecontemplated. At the flared portion 821 (FIG. 50) the return lumen 830transitions to a more circular configuration.

In the preferred embodiment, the intake lumens 840 a-840 d remainconstant throughout their length until the proximal flared portion 821where they are substantially circular (FIG. 50) and of greatercross-sectional area to receive the arterial extension tubes describedbelow. The intake lumens 840 a-840 d transition to a more arcuate shape,as shown in FIG. 48B, just proximal of the transition region 814, butthe cross-sectional area preferably remains the same. (This lumenconfiguration is similar to that of FIG. 9A in that it is more of atrapezoidal than oval shape with curved walls and inwardly angledsubstantially straight side walls). The cross-sectional area of eachintake lumen 840 is preferably about 0.003 inches² so that the totalintake cross-sectional area is preferably about 0.012 inches², but otherdimensions for the intake lumens are contemplated.

Turning now to the hub and tubing design for connecting the catheter 810to the dialysis machine tubing, and with reference to FIGS. 50 and 51,four arterial extensions tubes 850 a-850 d are each placed in arespective intake lumen 840 a-840 d at the flared portion 821 to providefluid communication. A sleeve 852 is attached during a thermal formingprocess to blend with the individual tubes 850 a-850 d to retain thefour arterial extension tubes 850 a-850 d together. A connector tube orinsert 854, preferably of stainless steel, is inserted into the centrallumen 830 and a tapered venous extension tube 856 is placed over thetube 854 to provide fluid communication between extension tube 856 andcentral lumen 830. The two hub halves 860, 862 of hub 861 are snappedfitted over the region containing flared portion 821, connector tube854, and a portion of extension tubes 850 a-850 d, 856 and sleeve 852 asshown in FIG. 51. Conventional arterial and venous clamps C1, C2,respectively, are illustrated in FIG. 45. In the preferred embodiment, asingle arterial clamp C1 would clamp on the sleeve 852 to cut off flowsimultaneously through all the arterial extension tubes 850 a-850 d.Thus separate arterial clamps would not be required. A luer lock 858 onvenous extension tube 856 is for mounting the stiffener rod, andsubsequent to insertion and after removal of the stiffener rod, formounting tubing for connection to the dialysis machine. The luer lockfor the arterial tubing mounts dialysis machine tubing.

A conventional suture ring 870 (FIG. 45), having suture holes forattaching the catheter, is fitted in an annular groove in the hub 861. Aconventional fibrous cuff 872 for tissue ingrowth is shown at anintermediate section of the catheter 810 for tissue ingrowth asdescribed above.

As described above, the catheters of the present invention arepreferably inserted with the aid of a stiffening rod. FIG. 49illustrates an embodiment of a stiffening rod for use with catheter 800to temporarily increase the stiffness of the catheter to facilitatepushability (insertion) of the catheter. Stiffening rod 880 has athickened wall portion 882 which engages an internal wall in the regionof the catheter adjacent the region which contains the stiffening insert820. Since this catheter region is not as flexible, it is not stretchedat this region by the stiffener rod 880, thus providing resistance todistal movement of the stiffening rod 880, thereby holding it in placeduring insertion.

The proximal end of the stiffener is threaded onto venous luer 858 (FIG.45). The increased wall thickness of stiffener rod 880 cooperates withthe distalmost tip of the catheter 800 to prevent coring of tissueduring insertion. The stiffener 880 protrudes past the distalmost tip ofthe catheter body 810 as shown, serving to help dilate tissue duringinsertion. Lumen 884 is dimensioned to receive a guidewire.

The arterial extension tubing includes a funneled lead in to facilitateinsertion of standard guidewires to clear obstructions, e.g. clots andthrombus, in the catheter arterial lumens which may form over time. Withreference to FIGS. 52-54, each of the quadrants within the sleeve has aninwardly directed curved inner wall 892 a-d to create a funnel for thetubing entry region.

The method of insertion of the catheter of the present inventionprovides an entire over the wire system. This is achieved by theprovision of trocar 300 illustrated in FIGS. 22 and 23. Trocar 300 has alumen 304 formed therethrough (shown in phantom in FIG. 22) dimensionedfor reception of guidewire 20. The lumen 304 extends the entire lengthof trocar 300, from a proximal opening 306 in handle 308 to a distalopening 310 (shown in phantom in FIG. 22) on the underside of the trocar300 as viewed in FIG. 22. Distal opening 310 is adjacent the distal tip302, at the region where it bends slightly upwardly. Note the lumen 304of trocar 300 can be smaller than the outer diameter of the dialysiscatheter, e.g. catheter 10, since it only needs to have an internaldiameter of about 0.040 inches to about 0.045 inches to receive theguidewire. The diameter of the catheter is typically between about 0.170inches and about 0.220 inches. The blunt distal tip 302 of trocar 300bluntly dissects tissue to create a subcutaneous tissue tunnel forsubsequent securement of the catheter.

FIGS. 24A and 24B illustrate an alternate embodiment of the trocar.Trocar 380 is similar to trocar 300 except for an elongated ovalentrance opening 382 to lumen 383 for the guidewire and a beveled tip384 to facilitate tunneling through tissue. The handle configuration 386is also slightly different.

One method of use of the catheter will now be described in conjunctionwith FIGS. 25 to 28. The method will be described for inserting catheter10, however it should be appreciated that any of the aforedescribedcatheters can be inserted in the same manner.

First, needle “N” is inserted into the internal jugular vein to properlylocate the vessel and a guidewire 20 is inserted through the needle intothe right internal jugular vein “a” and into the superior vena cava “b”as shown in FIG. 25. The guidewire 20 is further advanced into the rightatrium “c”, and preferably into the inferior vena cava. The needle “N”is then withdrawn, leaving the guidewire 20 in place, extending out ofthe patient's body at the proximal portion 21. Next, trocar 300 isinserted through a first incision “s” in the patient, bluntly dissectingand tunneling under the skin, and forced out of the tissue at a secondincision or site “u”, creating a subcutaneous tunnel “t” under thetissue as shown in FIG. 27. This provides a way to secure the catheteras described below. Guidewire 20 is then threaded through lumen 304 ofthe trocar, with proximal portion 21 first inserted through trocardistal opening 310 so it emerges out of proximal opening 306 as shown inFIG. 28A. Trocar 300 is then withdrawn from the body in the direction ofthe arrow of FIG. 28B, leaving the guidewire 20 in place as shown. Thus,guidewire 20 extends from the right atrium and superior vena cava, outthrough the right internal jugular vein and through the tissue tunnel“t”.

Catheter 10 is then threaded over the guidewire with the proximalportion 21 of the guidewire inserted through the distal tip lumen of thecatheter, through the length of the central lumen, and through the hub12 into the inflow tube 116 and out through fitting 15. The catheter 10is thus threaded over the wire, through the tissue tunnel “t” where cuff36 (not shown in FIG. 28C) is positioned in the tissue tunnel “t” to aidin securement of the catheter by enabling tissue ingrowth over a periodof time. The catheter is further advanced over guidewire 20 down intothe right internal jugular vein, into the superior vena cava, and intothe right atrium. The guidewire 20 is withdrawn in the direction of thearrow, leaving the catheter 10 in place for use as shown in FIG. 28C.Note the stiffening member 80 or 90 (not shown in FIG. 28C for clarity)is preferably utilized, i.e. inserted over the guidewire 20 through thefitting 15, inflow tube 16, hub 12, and central lumen 40 to help guidethe catheter 10 as described above. Thus, the guidewire 20 would extendthrough the central lumen of catheter by extending through the centrallumen of the stiffening member which is positioned within the centrallumen of the catheter.

As can be appreciated, the catheter will be inserted in a similarfashion through the left internal jugular vein to be positioned asdepicted in FIG. 2. In this method, the subcutaneous tissue tunnel willbe formed on the left side as shown in FIG. 2, by the trocar 300, andthe catheter inserted over the guidewire through the tissue tunnel andthrough the left internal jugular vein or subclavian vein and into thesuperior vena cava and right atrium in the same way as described forright side insertion. It should be understood that any of theaforedescribed catheters of the present invention can be inserted inthis fashion.

An alternative method of insertion is illustrated in FIGS. 29A-29G. Inthis method instead of forming a second incision site adjacent theincision site through which the needle and guidewire are introduced intothe internal jugular vein as in FIG. 27, the trocar 300 emerges from theneedle/guidewire insertion site. Although catheter 10 is shown, any ofthe foregoing catheters can be inserted in the same manner.

In this method, the needle and guidewire are inserted in an identicalmanner as illustrated in FIGS. 25 and 26. After removal of the needle,the guidewire 20 is left in place extending outwardly from the incisionsite, designated by “w”. Next, as shown in FIG. 29A, trocar 300 isinserted through a first incision (as in FIG. 27) to create asubcutaneous tissue tunnel; however, unlike FIG. 27, trocar 300 does notemerge at a second incision site “u”. Instead, trocar 300 is advancedsubcutaneously to the needle incision site “w”, and emerges through thesite “w” as shown. Thus, as shown in FIG. 29A, the distal end of trocar300′ exits incision site “w” alongside the guidewire 20.

Guidewire 20 is then inserted (threaded) through the opening in trocar300 as described above and then the trocar is withdrawn through thetissue tunnel “t” and out through the first incision “s”, pulling theguidewire 20 through the tunnel. After the guidewire 21 is pulledthrough the tunnel “t” and out through incision “s”, the trocar 300 isremoved as shown in FIG. 29B, leaving the guidewire 20 in place. Notethe guidewire 20 is positioned to form a guidewire loop 22 to facilitateinsertion of the catheter as will be described below.

The catheter 10 is then advanced over the guidewire 20 (FIG. 29C),through the tissue tunnel, and exiting incision site “w” into theinternal jugular vein “a” (FIG. 29D). The catheter 10, as shown, isformed into a loop 13, tracking the loop 22 of guidewire 20, and thenadvanced downwardly through the internal jugular vein, the superior venacava and into the right atrium (FIG. 29E). The guidewire 20 is thenwithdrawn as shown in FIG. 29F, and the catheter is pushed downwardlyand/or pulled back to straighten the loop to position the catheter asshown in FIG. 29G. If the catheter is inserted with a stiffening member,the guidewire would extend through the lumen of the stiffening member.

It should be appreciated that formation of the loop in the guidewire andthe catheter is optional and the procedure can be performed without theloop.

FIG. 30 shows an alternate embodiment of a trocar utilized to retrievethe suture and retract it through the subcutaneous tissue tunnel. Trocar300′ is similar to trocar 300 of FIG. 29 except for the provision ofeyelet 312. The suture is threaded through the eyelet (shown as twosmall opposing holes in the wall at the distal end of the trocar 300′)and the trocar is pulled proximally through the tissue tunnel to pullthe suture out through incision “s”. As shown, the trocar extendsthrough incision “w”, the same incision created for insertion of theneedle and guidewire.

Instead of an eyelet, a hook or other means can be provided on thetrocar for holding the guidewire to enable pulling the guidewire throughthe tissue tunnel. That is, in these versions, the guidewire is notthreaded through the trocar lumen, but rather the trocar is utilized topull (retract) the guidewire through the tissue tunnel.

FIG. 21A illustrates an alternative trocar used for a different approachto catheter insertion. This trocar, designated by reference numeral 350,does not provide for an entire over the wire system, however it is usedwith an approach providing a partial over the wire system whicheliminates the need for a tear way introducer sheath. As discussed inthe Background Section of this application, tear away introducer sheathsare currently being utilized to guide the dialysis catheter through thevessels into the right atrium. To avoid the problems associated with thetear away sheath, the catheter in this alternate method can be advancedover a guidewire which can be placed in the manner illustrated in FIGS.25 and 26.

In this method, trocar 350 is attached to the distal end of the catheterby insertion of barbed end 352 into a mating fitting. Other means fortemporarily attaching the trocar are also contemplated. Trocar 350 has ablunt distal tip 354 and is advanced through a first tissue incision andout through a second tissue incision, bluntly dissecting tissue andforming a subcutaneous tissue tunnel in a similar manner as describedabove, except without the guidewire. Since trocar 350 is attached to thecatheter, it pulls the catheter through the tissue tunnel, so it emergesout through the second incision. The trocar 350 is then detached fromthe catheter. The catheter is then bent as necessary and threaded overthe guidewire into jugular vein, superior vena cava, and right atrium.

FIGS. 21J-21M illustrate an alternate embodiment of the trocar used fora partial over the wire system. Trocar 390 has a proximal end portion392 and a distal end portion 394. The distal end portion has a dilatingtip 395 to facilitate insertion through a subcutaneous tissue tunnel.The proximal portion 392 progressively reduces in diameter toward theproximal end and has a radiused surface throughout its length to providean interference fit with the catheter. As shown, the proximal portion392 is inserted in the distal end of the catheter, until enlarged region393, which has a larger diameter than the diameter of the proximal endportion, abuts the catheter to limit insertion. As shown, the radiusedregion decreases in diameter (or transverse cross section toward theproximalmost end). The frictional engagement maintains the attachment asthe trocar 390, with its blunt tip, dissects tissue through the tunnelto advance the catheter through the tunnel. Once advanced through thetunnel, the guidewire can be threaded through the distal end and thecatheter inserted over the wire into the right atrium in the same manneras described above with respect to trocar 350.

FIGS. 21B-21H illustrate alternate embodiments of a trocar adapted tocreate a subcutaneous tissue tunnel and to subsequently be attached to acatheter. Trocar 900 and 920 each has a removable handle which isgrasped by the user and then inserted into the body to create thesubcutaneous tissue tunnel. The handle provides additional leverage forfacilitating trocar insertion/passage. Once inserted through the tunnel,the handle is detached and the trocar is attached to the dialysiscatheter as described above, for example, with reference to trocar 350of FIG. 21A. The distal end has a dilating distal tip as describedabove.

More specifically, in FIGS. 21B, 21C, 21E and 21F, trocar 900 has aconnecting structure 902 on a proximal end of the elongated body 903.The connecting structure 902 has a circumferential groove 904. Containedwithin the handle 906 is a latch 910 having an opening 912 dimensionedto receive tip 905 of connecting structure 902. The latch 910 is springbiased upwardly by spring 914 so that surface 916 is seated within agroove 904 to lock the elongated body 903 within handle 906. To releasethe handle 906, protruding region 918 of latch 910 is depressed, therebyforcing surface 916 out of groove 904 and placing tip 905 in alignmentwith opening 912 of latch 910 (shown in phantom in FIG. 21F). Thisenables the elongated body 903 of trocar 900 to be separated from thehandle 906. After such separation, which procedurally would occur afterthe trocar is inserted in the body to create a tissue tunnel t as inFIG. 21D, the connecting structure can be connected to a dialysiscatheter to pull the catheter through the tissue tunnel. It should beappreciated that the latch can alternatively engage the recess in thebarbed fitting 352 of trocar 350 of FIG. 21A.

In the embodiment of FIGS. 21D and 21G, the connecting structure 952extending from elongated body of trocar 950 comprises series of threads954. Handle 960 includes a bore with an internal thread for threadedconnection to thread 954. Thus, the elongated body 953 of trocar 950 canbe unthreaded and removed from handle 960 after creation of the tissuetunnel and then threadedly connected to the dialysis catheter.

It should also be appreciated that the threaded connection can be usedwith the trocar of FIG. 21A having a barbed fitting. This is shown inFIG. 21H. The threads 351 are positioned distally of the barbed fitting352′ with the trocar handle (not shown) having a bore with a firstregion dimensioned to receive the barb and having threads in a secondregion to engage the threads of the trocar. Similarly, if desired, thecircumferential groove of the embodiment of FIG. 21B can be placeddistal of the barbed fitting of the trocar of FIG. 21A. The bore of thetrocar handle would accommodate the barbed fitting plus include a latchto align with the region of the bore which receives the circumferentialgroove. In this manner, the barbed fitting would provide the connectingstructure for the dialysis catheter and the latch or threads wouldprovide the connecting structure for the trocar handle.

Turning now to one method of manufacturing the hub of the catheter, andwith particular reference to FIGS. 31-37, a method is disclosed whichenables connection of the central venous return (delivery) lumen of thecatheter with an inflow tube and fluid connection of the fiveindependent arterial intake (withdrawal) lumens with a single outflowtube to provide fluid connection through the connectors.

Turning first to FIG. 31, a longitudinal slit 201 is formed at aproximal portion of catheter tube 203. FIG. 32 shows the relationship ofthe slit 201 and the central venous lumen 205 as the slit is formed tocommunicate with the central lumen 205. As can be appreciated from thecross-sectional view of FIG. 33, the slit 201 is formed in the wall 206of the catheter tube 203 between adjacent arterial lumens 209 a-209 e.Next, a metal pin 207 is inserted through the slit 201 for the moldingprocess. Outer plastic venous tubing 210 is placed over the metal pin207 as shown in FIG. 35 to ultimately communicate with the central lumen205. Outer plastic arterial tubing 211 is also shown positioned over thecatheter tube 203 which will communicate with the arterial lumens 209.

Next, conventional injection molding techniques are utilized so the softplastic material flows around the catheter tube 203 and the metal pin207 as shown in FIG. 36. Then, the material is cooled to harden, forminga hub 208, with the metal pin 207 removed to form lumen 204. Lumen 204has a narrowed region 202. As shown in FIG. 37, lumen 204 fluidlyconnects lumen 207 of venous tube 210 with the central lumen 205 of thecatheter. Lumen 212 of arterial tubing 211 communicates with the fiveindependent arterial lumens 209.

FIGS. 38-39 illustrate another method for manufacturing the catheterconnections. In this method, catheter body 402 of catheter 400 isseparated into five segments 401 a-401 e at its proximalmost end,corresponding to each of the arterial (intake) lumens 403 a-403 e. FIG.40 illustrates the five cuts 408 made in the catheter wall 407 betweenthe adjacent arterial lumens 403 to form the five segments 401.

A separate arterial connector tube 412 a-412 e is positioned within arespective arterial lumen 403 a-403 e and is connected to a respectivesegment 401 a-401 e by solvent bonding or pressure fit. The proximal endof each connector tube 412 is positioned within arterial tube 414 whichtransports blood to the dialysis machine. Thus, blood flows through thearterial lumens 403, through each arterial connector tube 401 and into asingle arterial (intake) tube 414. It should be understood, that iffewer or larger number of arterial lumens are provided, then an equalamount of arterial tubes would be utilized as the arterial lumens wouldbe cut into the corresponding number of segments.

Venous (return) tubing 416 is connected to central venous lumen byvenous connector tube 410 which is attached inside the venous lumen bysolvent bonding, glue application or compression fit. Note that venousconnector tube 410 is positioned between the segments 401. FIGS. 41-43illustrate another alternate method for manufacturing the hub of thecatheter of the present invention. This hub and associated tubing isillustrated for use with a catheter having the lumen configuration ofFIG. 9C, although it can be utilized with other lumen configurations aswell.

A central lumen connector (intermediate) tube 702 is joined with centrallumen 78 of catheter 700. Four arterial connecting (intermediate) tubes704 are connected to a respective arterial lumen 76 a. These tubes eachhave a lumen that is substantially circular in cross-section along itslength. The substantially circular lumens corresponds to thecross-sectional shape of the arterial lumens within catheter 10 whichtransition from a substantially oval cross-sectional configuration to asubstantially circular cross-sectional configuration at the flaredproximal portion shown in FIG. 43. Note that venous lumen 78 alsotransitions to a substantially circular cross-sectional configuration.

Each of the connector tubes 704 is connected to multi-lumen extension(arterial) tube 708 which provides flow of blood to the dialysismachine. Extension tube 708 has a flared distal portion 711 with fourlumens 710, each configured for communicating with one of the connectortubes 704. As shown, each of the lumens 710 has a substantially circularcross-sectional configuration that transitions to a substantiallytriangular cross-sectional configuration towards the proximal portion.

Single lumen extension (venous) tube 712, which provides return of bloodto the patient, connects to connector tube 702. Tube 712 has a tapereddistal end 718 and its lumen 719 transitions from a substantiallycircular cross-sectional configuration to a substantially squareconfiguration toward the proximal end. Molding of housing 716 with theforegoing tubes forms the catheter hub. Conventional tube clamps, suchas clamps 17, 19 of FIG. 1, are placed around extension tubes 708, 712for cutting off blood flow.

A rotatable suture ring 720 is placed around the catheter hub andpreferably has a planar surface 722 to sit substantially flush with thepatient's skin. Suture holes 724 are configured to receive sutures forattaching the ring (and thus the catheter) to the patient.

An alternate embodiment of the proximal end portion of the catheter isillustrated in FIGS. 55-64. With particular reference to FIGS. 55 and56, catheter 1010 has a tube 1012 extending from hub 1020. (Theintermediate and distal end of tube 1012 is not shown) A venousextension tube 1030 and three arterial extension tubes 1040 a-c extendthrough the hub 1020 to communicate with the lumens of the catheter tube1012. A venous clamp 1032 is shown positioned over the venous tube 1030and an arterial clamp 1042 is shown positioned over the three arterialtubes 1040 a-c. An arterial tag 1044 and venous tag 1034, to provideindication of priming volume or other information, are shown attached tothe respective arterial and venous clamps. Cap 1035 is attached to theproximal end of the venous tube and is mounted within venous luer 1038.A cap 1045 is attached to the proximal end of the arterial tubes 1040a-c and is received within the arterial luer 1048. Cap 1045 includesthree aligned openings to receive the stacked tubes 1040 a, 1040 b and1040 c. An adapter 1043 is disposed within the luer 1048 and has threeopenings 1046 a arranged in a triangular fashion. (FIG. 60) Thistriangular arrangement maintains the arterial tubes in a radial fashionto better ensure injection of heparinized saline, contrast or otherfluids is evenly distributed among the three tubes. That is, the tubes1040 a, 1040 b, 1040 c are positioned adjacent each other and insubstantially the same plane, e.g. vertically in the orientation of FIG.56.

As shown, the arterial tubes 1040 a-c emerge from the adapter 1043 in atriangular/radial arrangement and then transition to the stackedarrangement through cap 1045, and enter hub 1020 in this verticalarrangement.

With reference to FIGS. 58, 59, and 63, the arterial clamp 1042 and tag1044 are shown in detail. Arterial clamp 1042 has a first arm 1042 aintegral with the second arm 1042 b and hingedly connected thereto formovement between an opened unclamped position and a closed clampedposition where latch 1047 a is engaged by edge 1047 b. The second arm1042 b includes two pairs of posts 1053 which limit lateral movement ofthe stacked arterial extension tubes 1040 a-c. FIGS. 63 and 64illustrate the tubes 1040 a, 1040 b, and 1040 c stacked (verticallyarranged in the orientation shown) in abutting relationship in the space1051 between the posts 1053. Extension 1057 of arm 1042 a engages thetopmost tube 1040 a to pinch the three tubes 1040 a-c to close off flowtherein.

During assembly, tag 1044 is attached to the clamp 1042. Tag 1044 hasbridge 1048 extending between walls 1044 a, 1044 b and two shortprojections 1049 a, 1049 b extending from each of the respective walls.FIG. 63 illustrates the tag with a portion broken away to illustrate thebridge 1048 and the projection 1049 a. That is, the wall 1044 a has beenremoved for clarity to illustrate the connection of the tag 1044 to theclamp 1042.

The venous clamp and tag are illustrated in FIGS. 61 and 62. The clamp1032 is shown in the neutral at rest position in FIG. 61A and FIG. 64,i.e. before latching of the arms 1033 a, 1033 b by latch 1031 engaged bythe edge of arm 1033 a. Tag 1034 has two bridges 1039 a and 1039 bextending between the walls 1037 a and 1037 b, and is placed on theclamp 1032 during assembly. FIG. 64 illustrates the tag 1034 with wall1037 b removed for clarity.

FIG. 57B illustrates a cross-sectional view of the catheter tube showingthe circular venous lumen 1011 and radially disposed arterial lumen 1013a-c, somewhat kidney shaped. As shown, opposite walls 1014 a, 1015 a arecurved, with adjoining walls 1116 a, 1116 b also radiused. The walls ofthe lumens 1013 b and 1013 c are likewise shaped and for clarity notlabeled. Longitudinally extending reinforcing ribs or wall extensions1024 (FIG. 57A), formed during the manufacturing step, are providedextending partially along the reduced diameter section 1021 of thecatheter to increase rigidity of the catheter. As shown, these ribs 1024terminate proximally of the venous lumen openings 1018 formed in thewall of the reduced diameter section 1017 of the catheter 1020. FIG. 57Cillustrates an alternative embodiment of the lumens, having thickerwalls between the lumens 2013 a, 2013 b and 2013 c to increase thestructural rigidity of the catheter and reduce kinking. For example, thethickness T1 of the wall W1 of FIG. 57C is greater than the thickness T2of wall W2 of FIG. 57B and the thickness T3 of wall W3 is greater thanthe thickness of T4 of wall W4 of lumen configuration of FIG. 57B. Asshown, opposite walls 2014 a, 2015 a of lumen 2013 a are curved, withadjoining walls 2016 a, 2016 b have a large radius. The walls of thelumens 1013 b and 1013 c are likewise shaped and for clarity notlabeled. The lumens can have various dimensions. In one embodiment ofthe lumen shape of FIG. 57C, each of the arterial lumens has the samedimension and is about 0.033 square inches in cross-section. The venouslumen in the illustrated embodiment is circular and in one embodimenthas a cross-sectional area of about 0.005 square inches. Otherdimensions are also contemplated.

The catheters described above can optionally include a surface treatmenton the exterior and/or the interior. The surface treatments can includefor example, a hydrophilic coating to increase lubricity and facilitateinsertion, a drug coating such as heparin or containing IIb, IIIainhibitors, inert coating substances such as Sorins carbon coating,and/or active coatings such as a silver ion coating.

It should be appreciated that although the catheter is described hereinas a dialysis catheter for hemodialysis, the catheter disclosed hereincould have other surgical applications, such as drug delivery or bloodsampling. Moreover, features of the catheter, tip configurations andlumen configurations can be utilized on other catheters.

While the above description contains many specifics, those specificsshould not be construed as limitations on the scope of the disclosure,but merely as exemplifications of preferred embodiments thereof. Thoseskilled in the art will envision many other possible variations that arewithin the scope and spirit of the disclosure as defined by the claimsappended hereto.

What is claimed is:
 1. A dialysis catheter comprising a first portionhaving a first diameter, an elongated distal portion having a seconddiameter smaller than the first diameter, and a transition portionbetween the first portion and distal portion, the first portionincluding first and second independent blood withdrawal lumens extendingin the first portion, the first withdrawal lumen terminating in thetransition portion in a first terminal opening and the second withdrawallumen terminating in a second terminal opening, the first and secondterminal openings being radially spaced and axially adjacent, and alongitudinally extending blood delivery lumen configured to deliverblood, the delivery lumen extending in the first portion and terminatingin a delivery opening in the distal portion of the catheter, the firstand second terminal openings positioned proximally of the deliveryopening, each of the first and second terminal openings having a curvedwall surrounding a portion of the terminal opening.
 2. The dialysiscatheter of claim 1, wherein the first and second withdrawal lumens havein cross section a first curved outer wall and a second curved innerwall opposite the first curved outer wall.
 3. The dialysis catheter ofclaim 2, wherein a length of the first curved outer wall is greater thana length of the second curved inner wall.
 4. The dialysis catheter ofclaim 3, wherein the first and second withdrawal lumens have arcuatewall portions joining the first curved outer wall and the second curvedinner wall.
 5. The dialysis catheter of claim 2, wherein each of thewithdrawal lumens has a third curved wall joining the first curved outerwall and the second curved inner wall.
 6. The dialysis catheter of claim3, wherein each of the withdrawal lumens has a third curved wall joiningthe first curved outer wall and the second curved inner wall.
 7. Thedialysis catheter of claim 6, wherein the first and second withdrawallumens have a substantially linear wall joining the first curved outerwall and the second curved inner wall.
 8. The dialysis catheter of claim1, wherein the delivery lumen is substantially circular incross-section.
 9. The dialysis catheter of claim 1, wherein the deliverylumen is aligned with a central longitudinal axis of the catheter. 10.The dialysis catheter of claim 1, wherein the first and secondwithdrawal lumens are radially spaced from the delivery lumen.
 11. Thedialysis catheter of claim 1, further comprising an opening in asidewall of the elongated distal portion for blood delivery.
 12. Thedialysis catheter of claim 1, wherein at least a portion of the wallthickness of the catheter in the distal portion tapers toward adistalmost end, the delivery lumen cross-sectional area remainingsubstantially constant throughout its length in the distal portion. 13.The dialysis catheter of claim 1, further comprising a stiffening memberremovably positionable within the blood delivery opening to increasestiffness of the catheter for insertion.
 14. A dialysis cathetercomprising a first portion having a first diameter, an elongated distalportion having a second diameter smaller than the first diameter, afirst blood withdrawal lumen extending in the first portion, the firstwithdrawal lumen having a first opening, and a longitudinally extendingblood delivery lumen configured to deliver blood, the delivery lumenextending in the first portion and terminating in a delivery openingspaced axially distally from the first opening of the withdrawal lumenand positioned in the distal portion of the catheter, the withdrawallumen radially spaced from the delivery lumen, and a spacer positionedbetween the first opening and the delivery opening such that thedelivery opening is positioned distal of the spacer and the firstopening is positioned proximal of the spacer, the spacer forming araised surface between the first opening and the delivery opening,wherein a transverse dimension of the catheter at the region of thespacer exceeds a transverse dimension of the catheter at the region atthe delivery opening.
 15. The catheter of claim 14, further comprising astiffening member received in the blood delivery lumen of the cathetersuch that the catheter with the stiffening member positioned therein isconfigured to be inserted into the patient.
 16. The catheter of claim15, wherein the stiffening member is removably attached to the catheter.17. The catheter of claim 15, wherein, the stiffening member has a lumenextending along a length to receive a guidewire therein.
 18. Thecatheter of claim 14, wherein the withdrawal lumen is non-circular incross section.
 19. The catheter of claim 14, wherein the delivery lumenis substantially circular in cross-section.